The semiconductor integrated circuit (IC) industry has experienced rapid growth. In the course of IC evolution, functional density (i.e., the number of interconnected devices per chip area) has generally increased while geometry size (i.e., the smallest component (or line) that can be created using a fabrication process) has decreased. This scaling down process generally provides benefits by increasing production efficiency and lowering associated costs. Such scaling down has also increased the complexity of an IC. In some applications, an IC includes different intellectual property (IP) block portions configured to be powered by power supply voltages having different voltage levels. An IP block portion incorporates an IP block that is a reusable circuit design and is usually the intellectual property of an IP block vendor. In some applications, even an IP block portion includes multiple circuit blocks configured to be powered by power supply voltages having different voltage levels.